The present invention relates to a lever-type transmission gear comprising a pair of coupled levers pivotable about spaced-apart axes extending approximately in parallel, and exhibiting a ratio between a driving and a driven side of the gear which is dependent on the position of the pair of levers.
A transmission gear of this type may comprise, for example, two levers connected in toggle-type manner, wherein the driving and driven elements may be formed of rods movable in a direction transverse with respect to one another. The rods are hinged to the toggle and, to a lever end remote therefrom and movable in the direction of the connecting straight line of the lever bearings remote from the toggle, or in a direction transverse thereto. The transmission ratio between driving and driven sides varies in response to the relative position of the levers, that is, in response to the angle formed by the levers in the area of their toggle-type connection. However, the design of this type of transmission gear offers only limited capabilities of variation of the position-dependent change in the transmission ratio through structural modification.